(1) Field of the Invention
The subject matter of this invention is the device for emergency cutting off fastened seatbelts in transport vehicles, especially automotive vehicles, the device having an elongated housing with an explosive charge or a pressure generator installed inside, connected with a system activating the drive of belt cutting, furnished with a cutting knife and a slot for that knife or a blade, and a gap for the seatbelt being cut in emergency if placed in the gap.
After an accident in which means of transport are involved drivers and passengers have difficulty in releasing from fastened seatbelts and leaving crashed vehicles, because of jammed seatbelt lock or not being able to have access to seatbelt lock, and because of after-accident shock, which especially refers to injured individuals, children, the disabled and the elderly. Fast leaving a vehicle by victims is very important as after such an accident there is a serious risk of fire of such a vehicle, the risk of being hit by other vehicles, or in a situation in which such a vehicle falls into water and sinks there is a serious threat to health and risk of fatality for individuals trapped in such a vehicle. Rescuing of injured passengers and a driver after accidents is always difficult because of fastened seatbelts.
(2) Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
A method of emergency cutting off fastened seatbelts, known from the Polish patent application PL-366686A1, especially after an accident, fire or other occurrence which causes abrupt change of a vehicle position, consists in determining, by control devices, if the following facts occurred: seatbelts fastening status, accident occurrence, time elapsed from the accident occurrence, ceasing uncontrolled movement of vehicle, activating seatbelt tensioners or airbags, or starting fire, and then, transmission of these signals to a processor which, depending on the type of signal, causes automatic cutting off seatbelt straps by a moving blade powered with a pyrotechnic/explosive charge.
From the Polish patent application PL386089A1 a device for automating cutting off seatbelts is also known, the device whose body has a tubular element connected with its housing, and this element is furnished with an explosive charge located near its bottom and a moving cutting segment furnished with a blade, installed inside this element. The device housing has a rectangular go-through gap for that blade, which seen from its side has the shape of a right-angled triangle or an obtuse-angled triangle. It is favourable when the cutting blade of the device has the shape of a rectangular strip or a rhombus, or a trapeze, or an arch-shaped element. In another embodiment of this device, the cutting segment is a pressing mandrel, fitted movably in the tubular body and fitted under it a movable blade of a cutter, connected by an articulated joint with one end of a fixed arm of the housing. A longitudinal go-through gap is made in the housing arm opposite to the cutter blade, and the bottom end of a cylindrical mandrel has a shape of a truncated cone. An explosive charge is fitted over the upper end of this mandrel.
A German description of a utility model DE29809585U1 discloses a device for cutting off a seatbelt, the device being made up of a two-part housing, one part of the two, attached to a transverse element of car body, is furnished with a fixed knife and the other part is furnished with a moving knife and an initiating set placed over h, driving the knife furnished with an initiator. Both parts, placed opposite each other, are furnished with rolls guiding the hip belt and the arm belt. After an airbag goes off, a delayed initiating impulse is given to the initiator and the latter initiates, in turn, the driving set, which causes the movement of the moving knife towards the fixed knife, and both seatbelts get cut off along the matching line of those two knives.
An international patent application W02006/109 106 A1 also discloses a device for quick releasing from fastened seatbelts, the device having a rectangular hollowed housing, furnished with an element attaching the flat section of a seatbelt and with a cutting element powered with an explosive element, having three controlling devices, and the cutting element has also a moving part with a blade directed towards the straight section of the seatbelt. The moving element having adequate inertial mass is situated in two guides attached to a support of the housing. Two out of three devices controlling the element, which actuates the cutting element, are actuated by hand and the other inertial element is actuated automatically, and one of the hand-operated controlling devices co-works with the removable device blocking the movable blade element. An explosive, flexible actuating devices, pushes the movable blade element towards the blocking element and shifts the movable element to its second position. Besides, an attaching element contains two locking elements positioned on both sides of the housing to keep a section of the seat belt straight, pressed between two walls of the housing and the fixing element. The housing has also an oblong gap inside and side walls. The moving element with a blade slides along the mentioned guides limited with the side walls of the housing, and the movable blade shins in the gap in the housing, powered by its moving element of appropriate inertial mass.
A French patent description FR2382902 proposes a device for cutting off the seatbelts, the device being made up of a cutting device, a device holding this cutting device in appropriate proximity to the belt being cut, a device storing energy necessary to cut this belt, a device sending a signal to activate the device storing energy, a sensing device connected with the energy storing device, the energy being adjusted to an abnormal situation, and the device being furnished with a pin pushing device located in an opening and a pusher with a bent spring pushing the mentioned pin along this opening towards the energy storing device. The spring device in tensioned position is held by a readily fusible wire which gets broken in response to activation of the sensing device, signalling an abnormal situation occurring, and the same causing the spring release and, in turn, activating the movement of the pusher pin. The aforementioned energy storing device is furnished with a chemical drive in the form of a blank cartridge, while the cutting device is made up of a blade and an anvil device between which the seatbelt runs. The cutting blade is fixed on a piston held in the opening of the holding device. The sensing device, on starting an abnormal condition, connects a source of electric current with this readily fusible wire melting it, and as a result the blank cartridge explodes and the piston with the blade is pushed outside and cuts the safety belt.
Patent description US 2008/0116681A1 discloses a device activated by an electronic control system to cut off the seatbelts. The seatbelt cut-off device comprises a seatbelt guillotine unit, a line for supplying pressurized gas from a gas cartridge to the guillotine unit, a cutter holder and a small cartridge cutter used to slice a gas cartridge membrane, a pressurized gas cartridge with a nozzle having a membrane preventing pressurized gas from releasing, a solenoid with a mounting bracket and a housing, and a striker pin used to push the pressurized gas cartridge.
The seatbelt cut-off device has a U-shaped housing fastened with screws, a double-sided blade—a V-shaped guillotine unit, connected with a piston shaft where a spring is located in order to prevent an inadvertent move of the piston shaft and cutting blade. The cut-off device has a webbing slot located perpendicularly to the cutting blade and the seatbelt is to be cut simultaneously by the two sides of the guillotine blade from the centre of the belt towards its sides. In this solution, following an accident, the solenoid is energized and moves the striker pin which pushes the pressurized gas cartridge. The pressurized gas cartridge, in turn, hits its nozzle on the small cuter which slices the membrane and releases pressurized gas which drives the double-sided cutting blade of the guillotine unit, which is to cut off the seatbelt.
The aforementioned solution is a complex and extended design comprising many parts. It takes a lot of space which limits its applicability in e.g. passenger cars. The design of the seatbelt cut-off device is not suitable for cutting off the seatbelt webbing used in means of transport. It is only a seemingly functional seatbelt cut-off device, because in this way it is not possible to cut off the seatbelt webbing used in the automotive industry. This is because perpendicular operation of a double-sided cutting blade or guillotine unit is unable to slice through flexible polyester fibres used in the seatbelt webbing all over the world according to UNECE Regulation No. 16 on international safety standards for automotive safety-belts.
All these features make the seatbelt cut-off device expensive and complex, which limits its applicability as an emergency device used in exceptional situations only.
The essential drawback of the seatbelt cutting design solutions known so far is that the flame caused by the pressure and resulting hot gases from burnt explosive charges are noxious for people remaining in the after-accident motor vehicle which, in turn, poses a risk of fire inside the vehicle cabin. Besides, most of known devices have sophisticated design, which has a negative impact on long-term efficiency and applicability in automotive vehicles. Furthermore, the sophisticated design requires specialized manufacture process engineering, which considerably increases the production costs.